DESCRIPTION: (Investigators' Abstract) In this proposal a concerted somatic cell and molecular genetic approach is described which should result in starting materials for the mapping of defined regions of the human genome. A complete panel of monochromosomal hybrids will be generated by the transfer of single, specific human chromosomes into recipient mouse fibroblasts. This panel will be made available to interested investigators and should be an important tool for the cloning of human gene sequences as well as for the physical mapping of the human genome. Conditions will also be determined for the most efficient utilization of microcell hybrids as donor cells for radiation hybrid mapping. Radiation hybrids will be made in a variety of cell lines. Optimization of all parameters affecting generation of radiation hybrids will also be tested. Furthermore, experiments are proposed to develop a second panel of monochromosomal hybrids designed specifically for utilization in radiation mapping experiments. With these resources, there should be no limits to the possibilities of mapping.